#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
int main()
{
	int a = 0;
	int b = 0;
	while(scanf("%d %d", &a, &b) != -1)
	{
		a = a ^ b;
		b = a ^ b;
		a = a ^ b;
		printf("%d %d", a, b);
	}
	return 0;
}